Exposure to Gasoline Vapour during Offloading of Tankers and Railway Wagons and Biological Multicomponent Monitoring

The purpose of this study was to measure the exposure of oil depot workers to gasoline vapour components during the offloading of tankers and railway wagons. We also compared the concentrations of airborne benzene, toluene and oxygenates with urinary concentrations of these components or their metabolites at the end of the shift and before the next shift as a means of assessing exposure during work shift. The workers in the offloading operations were chosen for the study because their exposure was expected to be relatively high, and there was no previous literature on the biological monitoring of coincident gasoline components in urine samples from these groups. In this study, all gasoline was unleaded, and either methyl tert-butyl ether (MTBE) alone or together with methyl tert-amyl ether (MTAE) were used as oxygenates to enhance the octane number and to ensure cleaner exhaust gases. The maximum oxygenate content varied from 12% in reformulated gasoline types to 15% in oxygenated types. In reformulated gasoline the content of aromatic hydrocarbons is also regulated to less than 30% and that of benzene to less than 1%. Several studies on road tanker drivers have described the exposure to gasoline vapour components 1‐3) , and the correlation between air and urine concentrations of gasoline components has been determined for post-shift and prenext-shift samples of MTBE under field conditions 2, 3) .